Plant-inspired adhesive and tough hydrogel based on Ag-Lignin nanoparticles-triggered dynamic redox catechol chemistry

Donglin Gan,Lili Jiang,Xiong Lu,Fuzeng Ren,Wensi Xing,Ju Fang,Kefeng Wang,Cancan Zhao,Liming Fang

doi:10.1038/s41467-019-09351-2

Abstract

Adhesive hydrogels have gained popularity in biomedical applications, however, traditional adhesive hydrogels often exhibit short-term adhesiveness, poor mechanical properties and lack of antibacterial ability. Here, a plant-inspired adhesive hydrogel has been developed based on Ag-Lignin nanoparticles (NPs)triggered dynamic redox catechol chemistry. Ag-Lignin NPs construct the dynamic catechol redox system, which creates long-lasting reductive-oxidative environment inner hydrogel networks. This redox system, generating catechol groups continuously, endows the hydrogel with long-term and repeatable adhesiveness. Furthermore, Ag-Lignin NPs generate free radicals and trigger self-gelation of the hydrogel under ambient environment. This hydrogel presents high toughness for the existence of covalent and non-covalent interaction in the hydrogel networks. The hydrogel also possesses good cell affinity and high antibacterial activity due to the catechol groups and bactericidal ability of Ag-Lignin NPs. This study proposes a strategy to design tough and adhesive hydrogels based on dynamic plant catechol chemistry.

Highlights

Adhesive hydrogels have gained popularity in biomedical applications, traditional adhesive hydrogels often exhibit short-term adhesiveness, poor mechanical properties and lack of antibacterial ability
The methoxyl and catechol groups of lignin are oxidized into quinone groups, as proved by cyclic voltammetry (CV) experiments, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS) analysis (Supplementary Figure 5, 6, 7 and 8, Supplementary Table 4, and Supplementary Notes 7–9)
acrylic acid (AA) monomers and pectin were mixed with the AgLignin NPs suspension to form the Ag-Lignin NPs-polyacrylic acid (PAA)/pectin nanocomposite hydrogel owing to the Ag-Lignin NPs-triggered free-radical polymerization under an ambient environment (Fig. 1a)

Summary

Introduction

Adhesive hydrogels have gained popularity in biomedical applications, traditional adhesive hydrogels often exhibit short-term adhesiveness, poor mechanical properties and lack of antibacterial ability. The hydrogel possesses good cell affinity and high antibacterial activity due to the catechol groups and bactericidal ability of Ag-Lignin NPs. This study proposes a strategy to design tough and adhesive hydrogels based on dynamic plant catechol chemistry. Mussel-inspired adhesive hydrogels with polydopamine (PDA) are typical examples of catechol-chemistry-based adhesive hydrogels[12,13,14] In these hydrogels, the catechol functional groups of PDA form covalent bonds/noncovalent bonds with different materials, and these hydrogels exhibit good adhesion to various surfaces[15]. Pure PDA-functionalized hydrogels generally have poor mechanical properties[16,17,18] and these adhesive hydrogels are not reusable[19] This is because some of the catechol groups in the adhesive hydrogel are converted to quinone groups through oxidation. The previous studies inspired us to propose a long-lasting adhesive hydrogel based on plant catechol chemistry

Methods

Results

Conclusion